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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/include/asm-generic/fixmap.h
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/*

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 * fixmap.h: compile-time virtual memory allocation

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 *

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 * This file is subject to the terms and conditions of the GNU General Public

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 * License.  See the file "COPYING" in the main directory of this archive

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 * for more details.

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 *

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 * Copyright (C) 1998 Ingo Molnar

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 *

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 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999

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 * x86_32 and x86_64 integration by Gustavo F. Padovan, February 2009

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 * Break out common bits to asm-generic by Mark Salter, November 2013

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 */

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#ifndef __ASM_GENERIC_FIXMAP_H

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#define __ASM_GENERIC_FIXMAP_H

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#include <linux/bug.h>

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#include <linux/mm_types.h>

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#define __fix_to_virt(x)	(FIXADDR_TOP - ((x) << PAGE_SHIFT))

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#define __virt_to_fix(x)	((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)

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#ifndef __ASSEMBLY__

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/*

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 * 'index to address' translation. If anyone tries to use the idx

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 * directly without translation, we catch the bug with a NULL-deference

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 * kernel oops. Illegal ranges of incoming indices are caught too.

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 */

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static __always_inline unsigned long fix_to_virt(const unsigned int idx)

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{

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	BUILD_BUG_ON(idx >= __end_of_fixed_addresses);

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	return __fix_to_virt(idx);

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}

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static inline unsigned long virt_to_fix(const unsigned long vaddr)

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{

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	BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);

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	return __virt_to_fix(vaddr);

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}

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/*

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 * Provide some reasonable defaults for page flags.

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 * Not all architectures use all of these different types and some

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 * architectures use different names.

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 */

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#ifndef FIXMAP_PAGE_NORMAL

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#define FIXMAP_PAGE_NORMAL PAGE_KERNEL

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#endif

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#if !defined(FIXMAP_PAGE_RO) && defined(PAGE_KERNEL_RO)

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#define FIXMAP_PAGE_RO PAGE_KERNEL_RO

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#endif

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#ifndef FIXMAP_PAGE_NOCACHE

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#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE

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#endif

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#ifndef FIXMAP_PAGE_IO

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#define FIXMAP_PAGE_IO PAGE_KERNEL_IO

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#endif

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#ifndef FIXMAP_PAGE_CLEAR

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#define FIXMAP_PAGE_CLEAR __pgprot(0)

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#endif

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#ifndef set_fixmap

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#define set_fixmap(idx, phys)				\

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	__set_fixmap(idx, phys, FIXMAP_PAGE_NORMAL)

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#endif

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#ifndef clear_fixmap

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#define clear_fixmap(idx)			\

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	__set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR)

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#endif

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/* Return a pointer with offset calculated */

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#define __set_fixmap_offset(idx, phys, flags)				\

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({									\

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	unsigned long ________addr;					\

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	__set_fixmap(idx, phys, flags);					\

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	________addr = fix_to_virt(idx) + ((phys) & (PAGE_SIZE - 1));	\

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	________addr;							\

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})

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#define set_fixmap_offset(idx, phys) \

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	__set_fixmap_offset(idx, phys, FIXMAP_PAGE_NORMAL)

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/*

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 * Some hardware wants to get fixmapped without caching.

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 */

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#define set_fixmap_nocache(idx, phys) \

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	__set_fixmap(idx, phys, FIXMAP_PAGE_NOCACHE)

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#define set_fixmap_offset_nocache(idx, phys) \

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	__set_fixmap_offset(idx, phys, FIXMAP_PAGE_NOCACHE)

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/*

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 * Some fixmaps are for IO

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 */

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#define set_fixmap_io(idx, phys) \

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	__set_fixmap(idx, phys, FIXMAP_PAGE_IO)

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#endif /* __ASSEMBLY__ */

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#endif /* __ASM_GENERIC_FIXMAP_H */

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